The Government seems intent on pursuing its renewables 'target' of such-and-such percent by 2020. This is one of the problems with our energy policy. It's target-driven rather than needs-driven.
The maths is neither complex not difficult to understand. The problem lies in the inability to recognise the truly massive amount of water or air required to generate a reasonable amount of electrical power. The laws of physics apply. They are understood, and there is no way around them.
Yet only a few weeks earlier, Lord Hunt, the Energy Minister, announced proposals to build 7,000 new wind turbines around the coast by 2020. The rated capacity of these turbines is 25GW, which means they might supply around 1.5GW (In Germany, a recent report stated that their 40GW of installed capacity actually gives about 2GW).
Media soundbites always use the 'rated capacity' of wind turbines when describing the number of homes which will be supplied with power. These soundbites are generally over-optimistic by a factor of between 10 and 20. They usually forget to mention that when the wind stops, or during strong winds, no power is generated at all. They always forget to mention that wind power generated at night is of no use to the Grid.
Another interesting letter from an engineer (RE, Ashtead), re-stated arguments put forward on this site three years ago (I have paraphrased part of it here):-
Whenever the wind turbines are operating there will be a need for a 'spinning reserve' of conventional plant running at part load ready to pick up or drop load if the wind speed falls or rises - the most inefficient way you can operate plant, and doing the national CO2 output no good at all.
There have been suggestions that the wind turbine output should be used to separate water into storable hydrogen and oxygen, by electrolysis. Unfortunately the energy loss is very high. The only way I can see of coping with this situation is to build more pumped storage hydro stations using the wind turbines to pump water to a higher level and then regenerate using hydraulic turbines when the output is needed.
Meanwhile, we have still not begun building any more nuclear stations. Their contribution to the Grid is now 12%, compared with about 22% fifteen years ago. The date approaches when more of our coal plant has to be switched off to meet European targets.
Malcolm Wicks, the Prime Minister's special representative on energy, said in early August that the current target of about 20% nuclear should be doubled, and more nuclear plants built. He wrote in a report that the country must reduce its dependence on fossil fuels, which are in unstable locations, unsustainable, and damaging to the environment.
Nuclear power is a proven, large-scale, low-carbon way to generate electricity", he said. "A range of between, say, 35 to 40 per cent of electricity from nuclear could be a sensible aspiration beyond 2030".
ND comment .... Mr. Wicks is right. But we'd get on a lot better if we forgot about 'targets' and concentrated on 'needs'.
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